Method of drying lumber



Patented May 6, 1930 UNITE STATES PATENT OFFICE J PEARL WILSON, OF JACKSONVILLE, FLORIDA, ASSIGNOR TO WILSON-OTWELL 8: CONE, INC., OF JACKSONVILLE, FLORIDA, A CORPORATION OF FLORIDA METHOD or DRYING LUMBER No Drawing.

This invention relates to an improvement in methods of drying lumber.

The object of the invention is to decrease the time required to dry various kinds of lumber and to dry it more thoroughly than in the usual manner, While at the same time increasing its quality, strength and texture.

This invention permits of drying such woods as pine, cypress, gum, etc., absolutely 10 without injury and also in about one third the time usually required for this purpose. It also dries the lumber more thoroughly, removing a greater percentage of the moisture, and saves at least five dollars per thousand 5 in manufacturing lumber.

The invention is especially good for use in connection with drying hard woods.

Heretofore, it has been the practice to saw the lumber and stack it in the yard between the saw and a dry kiln, keeping a big reserve always on hand so as to keep the dry kiln fillec. The lumber in this reserved supply was allowed to stand at least twenty-four hours after sawing before it is introduced into the dry kiln, and this is sufficient time in which to allow the pores of the lumber to close, holding the moisture therein and requiring a great deal of additional heat and steam to open these pores suificiently to evaporate the moisture, and in many instances a large amount of the moisture remains in the lumber. In addition to the use of a large amount of steam and heat, in opening the pores of the lumber which have once been allowed to close,

the lumber in the dry kiln for at least three times longer than is necessary or required by this invention.

It is the purpose of this invention to pass the lumber directly from the saw into the dry kiln before the pores are allowed to close. In this Way, the inte nseheat and humidity which must be kept very high and even throughout the dry kiln will cause the moisture contained in the lumber to evaporate quickly and evenly, and it is not therefore necessary to open the pores of the lumber in order to accomplish this. The dry kiln may be of the progressive type, that is, in 59 which the cars of fresh sawn lumber are inthe invention or is well it was necessary to keep Application filed August 30, 1927. Serial No. 216,494.

troduced in one end and moved progressively sawing operation may be started and, being located near the dry kiln in the usual manner,

the lumber may be passed directly from the saw into the kiln.

The heat of the kiln, being at least to the boiling point of water, 212 F. or above, will quickly evaporatethe moisture contained in the pores of the lumber, and since the latter .is fed into the dry kiln before the pores have had time to close it will cause a quick evaporating of the moisture contained in the pores of the lumber, accomplishing the drying operation in less time than could be done where the lumber is stacked or held in a'reverse supply between the saw and the dry kiln, as in theold method.

Thelengthof time at which the lumber may. remain in the open air after sawing and before beingintroduoed into the dry kiln depends entirely upon the kind of wood being dried, because the pores of some woods close up very much quicker than others, and this may be easily ascertained by those using known to those familiar with the art.

However, the important item is that the lumber should be introduced into the dry kiln after sawing and before the pores have had sufficient'opportunityto close, for after the pores are closed the moistureis trapped therein and it is necessary to subject the lumberto a high temperature for a'lon'ger period of time than here required in order to open these pores and then evaporate the moisture.

The results which have been obtained by the use of this invention indicate the great improvement which it is over the old method of drying lumber. This has been proved from a practical standpoint and in actual demonstrations, and it has been found that the lumber dries better and quicker than where it is allowed to stand in the open air for any considerable length of time, but so far as is known it has never been recognized before that the lumber could be dried better and quicker by introducing it directly in the dry kiln after sawing.

Reference in the claims to the closing of the pores of the lumber is intended to designate either a contraction of the cellular structure and/or a sealing of the pores due to the resins, sap, etc., contained in the Wood, which becomes oxidized to form a seal.

I claim 1. A method of drying lumber including removing the lumber from the sawing operation to an operating drying chamber before the pores of the lumber become closed.

2. A method of drying lumber including removing the lumber fromthe sawing operation into a drying chamber heated to a relatively high degree before the pores of the lumber become closed.

3. A method of drying lumber including removing the lumber from the sawing operation into a drying chamber, heated approximately to boiling point, for removing the moisture from the lumber and before the pores become closed.

l. A method of drying lumber including removing the lumber from sawing mechanism into a dry kiln, heated to at least boiling point by steam sprays and heating coils, before the pores of the lumber become closed in order to remove the moisture therefrom.

5. A method of drying lumber including first heating a dry kiln to at least boiling point before starting the sawing operation, and then removing the lumber from the sawing mechanism directly into the dry kiln before the pores of the lumber become closed in order to remove the moisture therefrom.

(3. A method of drying lumber including sawing the lumber, and immediately drying the lumber by subjecting it to artificial drying conditions before the pores of the sawed lumber become closed.

7. A method of drying lumber including subjecting the lumber to artificial drying conditions immediately after sawing and before the pores of'the sawed lumber become closed.

8. A method of drying lumber including subjecting the lumber to artificial drying conditions before the pores of the lumber become closed.

In testimony whereof I aiiix my signature.

J PEARL WILSON. 

